Large Blades

Pinoy Knife

Pinoy Knife

Joined
Aug 9, 2002
Messages
1,335
Greting's all
i need your help !! i have a customer who want's a large 2 feet plus blade that can take any "normal" cutting chores all day long without problem's . it is on a "Pole Arm " and used in M.A . ive made him a pair of 15 inch blades out of S-30 that have taken all the use/ abuse the customer can trow at them .
Im thinking of S-30 / A-2/5160/ Cable /L-6
What do you guy's recomend and why ??
who was it that was hunting racoon's with a bowie ? i remember them talking about hitting Concrete with no damage ! Please Reply if you can help decide
 
What's that S-7 "shock steel" or whatever? Don't know who carries it or who uses it, but it may be worth a look. I'm guessing most people will probably lean you toward 5160 or L6, probably, for something like that. I hope we get to see some pictures! :cool:
 
Matt, Chriswell used to use 5160 for his swords but has switched to A-2 since he feels it is more superiou to the 5160. He sends his blades some place on Swan Island for heat treat. Maybe you could contact him and maybe get him to slip your blade in with his. I've got several 3' bars of persision ground A-2 1/4 X 1 1/2" if your interested.
 
Pinoy Knife said:
who was it that was hunting racoon's with a bowie ? i remember them talking about hitting Concrete with no damage !
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Hehehe! :D I suppose it's nice that someone actually remembers, once in a while. Although I don't think I said no damage; my new knife is certainly better at taking abuse than my older ones. I still have to sharpen out small nicks, but I don't have near as much trouble with chipping, and this one hasn't actually broken yet! I believe there is still a bit of room for improvement though, according to my research...

I'll share some of my philosophies, but they may contradict the experiences of others, so take this for what it's worth.
For something this big, I have no use for stainless steel. I am after strength and impact resistance. I do not worry about wear resistance, because I've never had one of my big blades get dull through abrasive wear. I have to sharpen out nicks and other damage long before they ever get "dull". I used 5160 for my current blade, but if I knew then what I know now, I'd go with L6, CPM-3V, or one of the shock steels. (S5 or S7) Kevin Cashen has done some initial testing in his new lab, and his results seem to concur with industry literature. L6 can take almost double the impact forces of several other common knife steels. Take a look at this chart from Crucible, and you can google several others like it. According to people who know their steel, CPM-3V should have almost double the impact resistance of A2, and double the wear resistance. S7 has 3 or 4 times the impact resistance of several other knife steels we're used to.

I'm planning to use one of these steels for my next knife, and see if I can get better edge durability. If soft targets were all I ever had to cut, I'd still be using that big Pakistani POS I started out with. I had to make better tools to withstand the accidental, but inevitable, strikes against steel, concrete, teeth, etc.

My current blade is full flat ground, and 2 1/4 inches wide. (~5.7 cm) So, it does get thin at the edge. Before sharpening, I left the edge about as thick as a dime. (about 1.1 mm or so) I found out the hard way, that any thinner won't be stong enough to prevent ripples on botched cuts. Considering your pole arm would develop even more power in a swing, it would probably be a good idea to do a convex grind if it will work with your design.
 
Hey Matt!

I don't know if you are interested in going through the trouble to do the right heat treating, but it sounds like Bainite might be what you're looking for. There is a good discussion on it here at Don Fogg's forum. Scroll down to Brian Vanspeybroeck's post. It really sounds like this is tough stuff.

I'm just about set up to do marquenching/austempering now. However, I don't have a stainless vessel large enough to hold a 2' blade at 425 deg. for 10 hours right now. :eek:

Let me know if there's anything that I can do to help.

- Mike
 
Hi guys I just finished Putting the the pre-heat treat grinds on a blade. It is 5160 and 1/4" thick and the cutting edge is 12"(in case you're curious).

I would like a nice hamon on there if possible but will go without if I have to.
This is the first non-stainless knife I have made.

Anyone know where I can send it to get it heat treated?

I've also heard a torch can be used. Anyone with some experience please advise. Thanks.

Mike Coughlin
 
Guy's
i really appreciate all the offer's for help Mike / Ray . Mike i know about the Bainite . the only question i have is is it "Proven" better and by whom ?
Ray i really appreciate the offer of the A-2 i know where "Rob" get's his blades done ive used them for " stainless " im trying to get the " Expert's " out of the woodwork here !! ive talked to " Caffrey " and Hossum already one say's 3V one say's 5160 . i know either can be used .
im trying to find out if it can be ABUSED . this is a 2 foot long blade attached to a 4 3/4 feet long "Pole " the amount of impact on the blade is simply Huge. ive already built one in ''San Mai'' and it stand's up well but now the customer want's another !!
 
Matt,

To quote a post from the other thread...

For a hoot sometime, make two blades of 5160. Through harden one of them to make a Martensitic structure and then temper at the temp. of your choice to get the best ratio of tough to edge holding. Make one with the "Austenitze at 1550f and quench at 475f and hold for 10 hours..temper once at 475f for an hour" routine. Then, when they are sharpened and ready to go, cut phone books with them till they both get dull. Too dull to cut or slice a piece of paper. The Martensitic blade will outperform the Bainite blade by 15%.

Now (remember this is a hoot!!) take the two blades and crash them together edge to edge/back to back. Put them in a vise and bend them over 90 degrees. Now, post the pictures of the Martensitic blade with dime sized chunks snapped out of it's edge and permanently bent and the Bainite blade with a bigass laugh on it's face and a couple of insignificant nicks in it's edge where it beat the Martensitic blade to death.
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That sounds pretty tough to me. :eek: However, I don't have any personal experience with it yet.

- Mike
 
Greetings, Mr. Pinoy. I'd have responded sooner, but just got back from a 5 day trip.

I really wish I could give you a firm answer on whether bainite would be the best solution for you. I'd love to know that myself.
In fact, I should really tell you the rest of the story behind my bowie knife. Mr. VanSpeybroek turned me on to bainite himself on swordforums at the time. (though he later said he would have never helped me had he known what I'd be using the knife for. :rolleyes: I think we had a misunderstanding...) So, I ground out my blade from new 5160 stock I got from a leaf spring manufacturer, and sent it off to Joe Walters of Moonlit Forge to be heat treated to form bainite. Considering how tough bainite sounded, I was surprised by the edge damage I did get, and asked Joe about it. I ended up sending him some scraps I cut off of my bar, for him to test. He discovered it was very inconsistent, and even with a straight martensitic quench, varied in hardness throughout. Seems I got a bar from the end of a pour or something. So, my observations about bainite are not really valid. As I said, even with these inconsistensies, it's still doing better than the stainless I tried earlier.

Furthermore, tougher steels like I mentioned in my first post should also be able to beat a 5160 blade (martensitic) to death. Is 5160 bainite tougher than "regular" L6? Does martensitic L6 make a better blade than bainite L6? I don't know.

Since the praises of bainite have been sung, I suggest you see the other side of the coin, on this big thread on bainite.. I still don't know which would be better, but one thing that did come out of that discussion is that you really gotta know what you're doing to make bainite consistently. You gotta know the metalurgical theory, have precisely calibrated temps, the equipment to hold these temps, and put in lots of hard work and testing to make sure you're actually getting the structures you're after. It doesn't sound like something you could just jump into for one blade. If you wanna try it, you should probably have someone else experienced do the heat treat for you; otherwise stick with a tough steel in martensite.

Whatever you decide, I'm sure the others here would agree we'd love to hear how it goes.
 
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